Transmission line for drill pipes and downhole tools

ABSTRACT

A method of forming a wired pipe transmission line includes: providing an assembly that includes an inner conductor surrounded by an insulating material; attaching a fixation element to the assembly at or near an end thereof; providing a tubular outer conductor; disposing the assembly and the fixation element within the outer conductor; and fixedly attaching the fixation element to the inner portion of the tubular outer conductor.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of and claims the benefit of U.S. NonProvisional application Ser. No. 13/687618 filed Nov. 28, 2012, theentire disclosure of which is incorporated herein by reference.

BACKGROUND

During subterranean drilling and completion operations, a pipe or otherconduit is lowered into a borehole in an earth formation during or afterdrilling operations. Such pipes are generally configured as multiplepipe segments to form a “string”, such as a drill string or productionstring. As the string is lowered into the borehole, additional pipesegments are coupled to the string by various connection mechanisms,such as threaded couplings.

Various power and/or communication signals may be transmitted throughthe pipe segments via a “wired pipe” configuration. Such configurationsinclude electrical, optical or other conductors extending along thelength of selected pipe segments or string segments. The conductors areoperably connected between pipe segments by a variety of configurations.

One such configuration includes a threaded male-female configurationoften referred to as a pin box connection. The pin box connectionincludes a male member, i.e., a “pin end” that includes an exteriorthreaded portion, and a female member, i.e., a “box end”, that includesan interior threaded portion and is configured to receive the pin in athreaded connection.

Some wired pipe configurations include a transmission device mounted onthe tip of the pin end as well as in the box end. The transmissiondevice, or “coupler,” can transmit power, data or both to an adjacentcoupler. The coupler in the pin end is typically connected via a coaxialcable or other means to the coupler in the box end.

BRIEF DESCRIPTION

Disclosed herein is a wired pipe system that includes a wired pipesegment having a first end and a second end and a first coupler in thefirst end and a second coupler in the second end. The system alsoincludes a transmission medium disposed in the wired pipe segmentbetween the first and second ends and providing at least part of anelectrical path between the first and second couplers. The transmissionline includes an assembly that includes an inner conductor surroundedover at least a portion of its length by an insulating material, afixation element surrounding and attached to the assembly at or near anend of the assembly, and an outer conductor surrounding at least aportion of a length of the assembly and the fixation element, the outerconductor being fixedly connected to the fixation element.

Also disclosed is method of forming a wired pipe transmission line thatincludes: providing an assembly that includes an inner conductorsurrounded by an insulating material; attaching a fixation element tothe assembly at or near an end thereof; providing a tubular outerconductor; disposing the assembly and the fixation element within theouter conductor; and fixedly attaching the fixation element to the innerportion of the tubular outer conductor.

Also disclosed is a wired pipe system comprising: a wired pipe segmenthaving a first end and a second end; a first coupler in the first endand a second coupler in the second end; and a transmission mediumdisposed in the wired pipe segment between the first and second ends andproviding at least part of an electrical path between the first andsecond couplers, the transmission medium comprising: an assembly thatincludes an inner conductor surrounded over at least a portion of itslength by an insulating material; a plurality of separate, spaced-apartfixation elements surrounding and attached to the assembly at or near anend of the assembly; and a wire channel surrounding at least a portionof a length of the assembly and the fixation element, the wire channelbeing fixedly connected to the fixation element.

BRIEF DESCRIPTION OF THE DRAWINGS

The following descriptions should not be considered limiting in any way.With reference to the accompanying drawings, like elements are numberedalike:

FIG. 1 depicts an exemplary embodiment of a wired pipe segment of a welldrilling and/or logging system;

FIG. 2 depicts an exemplary embodiment of a box end of the segment ofFIG. 1;

FIG. 3 depicts an exemplary embodiment of a pin end of the segment ofFIG. 1;

FIG. 4 shows a perspective view of a transmission line;

FIG. 5 shows a perspective view of an end of transmission element;

FIG. 6 shows an cut-away side view of an end of transmission line;

FIG. 7 shows a cut-away section of a transmission line; and

FIGS. 8A and 8B show, respectively, perspective and cut-away side viewsof an embodiment of a transmission line.

DETAILED DESCRIPTION

A detailed description of one or more embodiments of the disclosedsystem, apparatus and method are presented herein by way ofexemplification and not limitation with reference to the Figures.

Referring to FIG. 1, an exemplary embodiment of a portion of a welldrilling, logging and/or production system 10 includes a conduit orstring 12, such as a drillstring or production string, that isconfigured to be disposed in a borehole for performing operations suchas drilling the borehole, making measurements of properties of theborehole and/or the surrounding formation downhole, or facilitating gasor liquid production.

For example, during drilling operations, drilling fluid or drilling“mud” is introduced into the string 12 from a source such as a mud tankor “pit” and is circulated under pressure through the string 12, forexample via one or more mud pumps. The drilling fluid passes into thestring 12 and is discharged at the bottom of the borehole through anopening in a drill bit located at the downhole end of the string 12. Thedrilling fluid circulates uphole between the string 12 and the boreholewall and is discharged into the mud tank or other location.

The string 12 may include at least one wired pipe segment 14 having anuphole end 18 and a downhole end 16. As described herein, “uphole”refers to a location near the point where the drilling started relativeto a reference location when the segment 14 is disposed in a borehole,and “downhole” refers to a location away from the point where thedrilling started along the borehole relative to the reference location.It shall be understood that the uphole end 18 could be below thedownhole end 16 without departing from the scope of the disclosureherein.

At least an inner bore or other conduit 20 extends along the length ofeach segment 14 to allow drilling mud or other fluids to flowtherethrough. A transmission line 22 is located within the wired segment14 to provide protection for electrical, optical or other conductors tobe disposed along the wired segment 14. In one embodiment, thetransmission line 22 is a coaxial cable. In another embodiment, thetransmission line 22 is formed of any manner of carrying power or data,including, for example, a twisted pair. In the case where thetransmission line 22 is a coaxial cable it may include an innerconductor surrounded by a dielectric material. The coaxial cable mayalso include a shield layer that surrounds the dielectric material. Inone embodiment, the shield layer is electrically coupled to an outerconductor that may be formed, for example, by a rigid or semi-rigid tubeof a conductive material.

The segment 14 includes a downhole connection 24 and an upholeconnection 26. The segment 14 is configured so that the upholeconnection 26 is positioned at an uphole location relative to thedownhole connection 24. The downhole connection 24 includes a maleconnection portion 28 having an exterior threaded section, and isreferred to herein as a “pin end” 24. The uphole connection 26 includesa female connection portion 30 having an interior threaded section, andis referred to herein as a “box end” 26.

The pin end 24 and the box end 26 are configured so that the pin end 24of one wired pipe segment 14 can be disposed within the box end 26 ofanother wired pipe segment 14 to effect a fixed connection therebetweento connect the segment 14 with another adjacent segment 14 or otherdownhole component. In one embodiment, the exterior of the maleconnection portion 28 and the interior of the female connection portion30 are tapered. Although the pin end 24 and the box end 26 are describedhas having threaded portions, the pin end 24 and the box end 26 may beconfigured to be coupled using any suitable mechanism, such as bolts orscrews or an interference fit.

In one embodiment, the system 10 is operably connected to a downhole orsurface processing unit which may act to control various components ofthe system 10, such as drilling, logging and production components orsubs. Other components include machinery to raise or lower segments 14and operably couple segments 14, and transmission devices. The downholeor surface processing unit may also collect and process data generatedby the system 10 during drilling, production or other operations.

As described herein, “drillstring” or “string” refers to any structureor carrier suitable for lowering a tool through a borehole or connectinga drill bit to the surface, and is not limited to the structure andconfiguration described herein. For example, a string could beconfigured as a drillstring, hydrocarbon production string or formationevaluation string. The term “carrier” as used herein means any device,device component, combination of devices, media and/or member that maybe used to convey, house, support or otherwise facilitate the use ofanother device, device component, combination of devices, media and/ormember. Exemplary non-limiting carriers include drill strings of thecoiled tube type, of the jointed pipe type and any combination orportion thereof. Other carrier examples include casing pipes, wirelines,wireline sondes, slickline sondes, drop shots, downhole subs, BHA's anddrill strings.

Referring to FIGS. 2 and 3, the segment 14 includes at least onetransmission device 34 (also referred to as a “coupler” herein) disposedtherein and located at the pin end 24 and/or the box end 26. Thetransmission device 34 is configured to provide communication of atleast one of data and power between adjacent segments 14 when the pinend 24 and the box end 26 are engaged. The transmission device 34 may beof any suitable type, such as an inductive coil, direct electrical(e.g., galvanic) contacts and an optical connection ring. The couplermay be disposed at the inner or outer shoulder. Further, thetransmission device 34 may be a resonant coupler It shall be understoodthat the transmission device 34 could also be included in a repeaterelement disposed between adjacent segments 14 (e.g, within the box end).In such a case, the data/power is transmitted from the transmissiondevice in one segment, into the repeater. The signal may then be passed“as is,” amplified, and/or modified in the repeater and provided to theadjacent segment 14.

Regardless of the configuration, it shall be understood that eachtransmission device 34 can be connected to one or more transmissionlines 22 by connector 23. Embodiments disclosed herein are directed tohow the transmission lines 22 can be formed and disposed in a segment14. In one embodiment, the transmission line 22 is capable ofwithstanding the tensile, compression and torsional stresses andsuperimposed dynamic accelerations typically present in downhole toolswhen exploring oil, gas or geothermal wells.

In one embodiment, the transmission line 22 includes a wire channel(e.g., an outer protective layer) and a transmission element. Thetransmission element can be selected from one of coaxial cable, twistedpair wires, and individual wires. The following description is presentedwith respect to coaxial wire but it shall be understood that theteachings herein are applicable to any type of transmission element. Inone embodiment, tension is created in the transmission element withrespect to one or both the wire channel and the body of the segment 14.This tension may help to abate independent motion between thetransmission element and the wire channel.

Referring now to FIG. 4, an example of a transmission line 22 isillustrated in a perspective view. The transmission line 22 includes awire channel 100 (shown in phantom) surrounding a transmission element102. The wire channel in the illustrated embodiment includes anattachment shoulder 106 that can be used rigidly to join it to a segment14 (FIG. 1). In one embodiment, the wire channel 100 is formed as a tubeof an electrically conductive rigid material such as steel and the like.In this manner, the wire channel 100 is electrically coupled to the bodyof the segments 14 and, as such, is connected to ground.

The transmission element 102 can be any type of element that cantransmit an electric signal. This includes, without limitation, acoaxial cable, a twisted pair of wires and individual wires. Given thatthe wire channel 100 is at a ground level, it shall be understood thatthe conductive elements of the transmission element 102 are typicallysurrounded over at least a portion of its length by one or more layersof an insulating material, such as a dielectric, to electrically andphysically separate them from the wire channel 100.

Fixation elements 104 are located at or near one or both ends (e.g., inan end region) of the transmission element 102 in general and theinsulating material in particular. The fixation elements 104 serve tofixedly attach the transmission element 102 within the wire channel 100.In one embodiment, the attachment is such that the transmission element102 is in tension with respect to the wire channel 100.

As best seen in FIG. 5, in one embodiment, the transmission element 102includes an inner conductor 201 surrounded by an insulating layer 202.The inner conductor 201 can be, for example, a solid or stranded wire ora hollow metal tube. The insulating layer 202 is formed of a dielectricmaterial in one embodiment. In one embodiment, the inner conductor 201extends beyond an end of the insulating layer 202. Such an extension canallow for electrical connection of the inner conductor 201 to anotherelement such as the coupler 34 or a connector attached to the coupler 34(FIG. 1).

As illustrated, one or more additional layers 203 surround theinsulating layer 202 and these layers can include, for example anelectrical shielding layer and one or more additional insulating layers.In one embodiment, the insulating layer 202 is formed such that there islittle to no relative movement between the insulating layer 202 and theinner conductor 201. As further explained below, no deformation of thechannel 100 is required to substantially fix the insulating layer 202relative to the inner conductor 201. Further, in the event that theinner conductor 201 is hollow, an expansion of it is not needed tosubstantially fix the insulating layer 202 relative to the innerconductor 201.

As illustrated, the end of the insulating layer 205 extends beyond anend 204 of the fixation element 104 but this is not required. Thefixation element 104 may be formed onto the transmission element 102 ina variety of non-compressive manners. For instance, the fixation element104 could be cold worked on to the transmission element. Alternatively,the fixation element could be glued, chemically or thermally bonded, orelastically clamped to the transmission element 102. In such cases, theportions of the transmission element 102 surrounded by the fixationelement may be specially designed, treated and prepared for suchpurpose.

As shown in FIG. 4, the fixation elements 104 are shown as extendingalong only a portion of the length of the transmission element 102 in aregion at or near the ends thereof. In one embodiment, the fixationelements 104 are less than about 1 meter long. In another embodiment,one or more of the fixation elements 104 do not extend for more than1/10^(th) of the length of the transmission element 102. As thetransmission element 102 spans most of the length of a particularsegment 14 (FIG. 1), its length can be about 9 meters in one embodiment.

Regardless of how attached, it shall be understood that the transmissionelement is, in one embodiment, a tube of metal or another rigidmaterial. After being attached to the transmission element 102, theassembly that includes the transmission element 102 and the fixationelements 102 can be inserted into the wire channel 100. The fixationelements 104 are then secured to the wire channel 100. The fixationelement 104 may be secured to the wire channel 100 by means of welding,soldering, gluing, or plastically deforming the wire channel 100.Alternative means of fixing the fixation element 104 are shown below.

FIG. 6 shows a cut-away side view of a region at or near an end of thetransmission line 22 shown in FIG. 4. The wire channel 100 extendsbeyond an end 220 of the communication element 201 in this embodiment.The fixation element 104 can be coupled to the transmission element 102as described above. After being inserted into the wire channel 100, thefixation element 104 can be press fit or fitted tightly into the wirechannel 100, glued, soldered, clamped (with suitable clamping elementslike tapered rings) or held by compression caused when forming the wirechannel 100 onto the fixation element 104. Unlike in other applicationsonly this short portion of the wire has to be fixed with respect to thewire channel 100 in order to prevent the transmission element 102 frommoving with respect to the wire channel 100.

FIG. 7 shows a cut-away perspective view of a transmission line 22 thatexemplifies the fact that a gap 230 can be formed between thetransmission element 102 and the wire channel 100 between the fixationelements 104 disposed at the distal ends of the transmission element102. In this embodiment, the transmission element 102 is illustrated asincluding two optional additional layers 203 a, 203 b that may be,respectively, a shield layer and an insulating layer. In this embodimentthe communication element 201 does extend beyond the dielectric layer202.

In one embodiment, the length of the assembly including the fixationelements 104 and the transmission element 102 may be held in compressiveload in all conditions. This may be achieved by manufacturing theassembly such that it is longer than actually needed in finalinstallation. In such a case, as the assembly is placed in the wirechannel 100 the transmission element is compressed or otherwise deformedaxially such that fixation elements 104 can be affixed to an inner wallof the wire channel. If then later during the installation or while inuse in a drill string the wire channel 100 gets elongated thetransmission element 102 may still remain in operative contact withother elements and may, in some cases, remain in compression.

In one embodiment, the gap 230 may be filled with a material that servesto support the transmission element 102 within the wire channel 100.Suitable materials included fluids, glue, chemically activated glues,heat activated glues, etc. In addition, the material in the gap 230 mayalso support the transmission element 102 so as to prevent any lateralmovement of it inside the wire channel 100. In such a case, otherfilling materials in adding to the glues and fluid disclosed above maybe utilized. For instance, the gap 230 could be filled with an elastomeror microspheres. Microspheres can be provided within the gap 230 and, asis known in the art, can increase their respective volume when exposedto heat. This volume change may serve to clamp the transmission element102 tightly within the wire channel 100 without the need to chemicallybond it to the channel.

FIGS. 8A and 8B show, respectively, perspective and cut-away side viewsof an end of a transmission line 22. As before, the transmission line 22includes a transmission element 102 that includes an inner conductor 201and an insulating layer 202. In this embodiment, the fixation element104 includes threads on one or both of an interior or exterior portionthereof. As illustrated, the fixation element 104 includes internalthreads 603 and external threads 605. In one embodiment, the internalthreads 603 can be omitted and the fixation element 104 can be fixedlyattached to one another as described above. In the illustratedembodiment, the internals threads 603 mate with the insulating layer202. As shown, an optional shielding layer 601 is disposed between theinsulating layer 202 and the fixation element 104. In the illustratedembodiment, the interaction of the internal threads 603 and theinsulating layer 202 aids in holding them in a fixed relationshiprelative to one another. Of course, adhesives could also aid in suchfixation.

The external threads 605 mate with wire channel internal threads 607. Inthis manner, transmission element 102 can be held in a fixed positionrelative to the wire channel 100.

While both the fixation elements and wire channels shown above are inthe form of tubular elements, it shall be understood that these elementscould be formed by combing two half shells together by, for example,welding or chemical bonding.

Set forth below are some embodiments of the foregoing disclosure:

Embodiment 1: A wired pipe system comprising: a wired pipe segmenthaving a first end and a second end; a first coupler in the first endand a second coupler in the second end; and a transmission mediumdisposed in the wired pipe segment between the first and second ends andproviding at least part of an electrical path between the first andsecond couplers, the transmission medium comprising: an assembly thatincludes an inner conductor surrounded over at least a portion of itslength by an insulating material; a plurality of separate, spaced-apartfixation elements surrounding and attached to the assembly at or near anend of the assembly; and a wire channel surrounding at least a portionof a length of the assembly and the fixation element, the wire channelbeing fixedly connected to the fixation element.

Embodiment 2: The wired pipe system of embodiment 1, wherein the wirechannel extends beyond an end of at least one of the inner conductor andthe insulating material.

Embodiment 3: The wired pipe system of embodiment 1, further comprising:a connector disposed at least partially between the assembly and acommunication coupler, the connector electrically connecting thecommunication coupler to the inner conductor.

Embodiment 4: The wired pipe system of embodiment 3, wherein theconnector is at least partially disposed within the wire channel.

Embodiment 5: The wired pipe system of embodiment 4, wherein a portionof the inner conductor extends beyond an end of the insulating materialand is in electrical contact with the connector.

Embodiment 6: The wired pipe system of embodiment 1, wherein thefixation elements are glued to the assembly.

Embodiment 7: The wired pipe system of embodiment 1, wherein thefixation elements are cold worked on to the assembly.

Embodiment 8:The wired pipe system of embodiment 1, wherein the fixationelements are chemically or thermally bonded to the assembly.

One skilled in the art will recognize that the various components ortechnologies may provide certain necessary or beneficial functionalityor features. Accordingly, these functions and features as may be neededin support of the appended claims and variations thereof, are recognizedas being inherently included as a part of the teachings herein and apart of the invention disclosed.

While the invention has been described with reference to exemplaryembodiments, it will be understood by those skilled in the art thatvarious changes may be made and equivalents may be substituted forelements thereof without departing from the scope of the invention. Inaddition, many modifications will be appreciated by those skilled in theart to adapt a particular instrument, situation or material to theteachings of the invention without departing from the essential scopethereof. Therefore, it is intended that the invention not be limited tothe particular embodiment disclosed as the best mode contemplated forcarrying out this invention, but that the invention will include allembodiments falling within the scope of the appended claims.

The use of the terms “a” and “an” and “the” and similar referents in thecontext of describing the invention (especially in the context of thefollowing claims) are to be construed to cover both the singular and theplural, unless otherwise indicated herein or clearly contradicted bycontext. Further, it should further be noted that the terms “first,”“second,” and the like herein do not denote any order, quantity, orimportance, but rather are used to distinguish one element from another.The modifier “about” used in connection with a quantity is inclusive ofthe stated value and has the meaning dictated by the context (e.g., itincludes the degree of error associated with measurement of theparticular quantity).

The teachings of the present disclosure may be used in a variety of welloperations. These operations may involve using one or more treatmentagents to treat a formation, the fluids resident in a formation, awellbore, and/or equipment in the wellbore, such as production tubing.The treatment agents may be in the form of liquids, gases, solids,semi-solids, and mixtures thereof. Illustrative treatment agentsinclude, but are not limited to, fracturing fluids, acids, steam, water,brine, anti-corrosion agents, cement, permeability modifiers, drillingmuds, emulsifiers, demulsifiers, tracers, flow improvers etc.Illustrative well operations include, but are not limited to, hydraulicfracturing, stimulation, tracer injection, cleaning, acidizing, steaminjection, water flooding, cementing, etc.

While the invention has been described with reference to an exemplaryembodiment or embodiments, it will be understood by those skilled in theart that various changes may be made and equivalents may be substitutedfor elements thereof without departing from the scope of the invention.In addition, many modifications may be made to adapt a particularsituation or material to the teachings of the invention withoutdeparting from the essential scope thereof. Therefore, it is intendedthat the invention not be limited to the particular embodiment disclosedas the best mode contemplated for carrying out this invention, but thatthe invention will include all embodiments falling within the scope ofthe claims. Also, in the drawings and the description, there have beendisclosed exemplary embodiments of the invention and, although specificterms may have been employed, they are unless otherwise stated used in ageneric and descriptive sense only and not for purposes of limitation,the scope of the invention therefore not being so limited.

What is claimed is:
 1. A wired pipe system comprising: a wired pipesegment having a first end and a second end; a first coupler in thefirst end and a second coupler in the second end; and a transmissionmedium disposed in the wired pipe segment between the first and secondends and providing at least part of an electrical path between the firstand second couplers, the transmission medium comprising: an assemblythat includes an inner conductor surrounded over at least a portion ofits length by an insulating material; a plurality of separate,spaced-apart fixation elements surrounding and attached to the assemblyat or near a single end of the assembly; and a wire channel surroundingat least a portion of a length of the assembly and the fixation element,the wire channel being fixedly connected to the fixation element.
 2. Thewired pipe system of claim 1, wherein the wire channel extends beyond anend of at least one of the inner conductor and the insulating material.3. The wired pipe system of claim 1, further comprising: a connectordisposed at least partially between the assembly and a communicationcoupler, the connector electrically connecting the communication couplerto the inner conductor.
 4. The wired pipe system of claim 3, wherein theconnector is at least partially disposed within the wire channel.
 5. Thewired pipe system of claim 4, wherein a portion of the inner conductorextends beyond an end of the insulating material and is in electricalcontact with the connector.
 6. The wired pipe system of claim 1, whereinthe fixation elements are glued to the assembly.
 7. The wired pipesystem of claim 1, wherein the fixation elements are cold worked on tothe assembly.
 8. The wired pipe system of claim 1, wherein the fixationelements are chemically or thermally bonded to the assembly.